Linux founder tells Intel to stop inventing 'magic instructions' and'start fixing real problems'

Linus Torvalds' comments came from this article: https://is.gd/6zpZRL

His comments came in a mailing list (via Phoronix) discussing an article suggesting AVX-512 might not be part of Intel's upcoming Alder Lake architecture. If that comes to pass, it will be just fine by Torvalds.

"I hope AVX512 dies a painful death, and that Intel starts fixing real problems instead of trying to create magic instructions to then create benchmarks that they can look good on. I hope Intel gets back to basics: gets their process working again, and concentrate more on regular code that isn't HPC or some other pointless special case," Torvalds said.

Intel introduced AVX-512 in 2013, initially as part of its Xeon Phi x200 and Skylake-X processor lines. It has also found its way into more current CPU architectures, including Ice Lake.

The instruction set is designed to bolster performance in various types of workloads, such as scientific simulations, financial analytics, artificial intelligence, data compression, and other tasks that can benefit from more robust floating point operations.

Nevertheless, Torvalds views AVX-512 as an example of "special-case garbage," noting that in regards to floating point performance, "absolutely nobody cares outside of benchmarks."

"I absolutely detest FP benchmarks, and I realize other people care deeply. I just think AVX-512 is exactly the wrong thing to do. It's a pet peeve of mine. It's a prime example of something Intel has done wrong, partly by just increasing the fragmentation of the market," Torvalds said.

I think he's absolutely right, and previously we didn't see how much
Intel was wasting its time making these AVX instructions because it's
gaping security flaws were not yet known. We just assumed that the more
sophisticated these floating-point instructions got, the more power they
must draw naturally. But previous generations of FP instructions stayed
well within the power envelope of the processor, whereas these AVX
instructions have been known to go well outside the standard power envelope.

Yousuf Khan

Yousuf Khan wrote:

Linus Torvalds' comments came from this article: https://is.gd/6zpZRL

Full URL:
https://www.pcgamer.com/linux-founde...al-problems%2F

Linus is known for publishing his tirades on Windows, and even on Linux
variants. He lambasts everyone.

Tweaking hardware to look good in benchmarks is news to you? Video chip
makers have been doing this forever, making their hardware or firmware
look better in particular benchmarks (sometimes their own benchmarks
tweaked for their hardware) but for which the benchmarks have no
practical implementation illustrating actual performance in real use.

AVX wasn't just about improving FP instructions. The number of cores
available back then was maybe up to 4 allowing concurrent thread
processing. With more cores to parallelize the computing, AVX becomes
less necessary. The latest CPUs (although far outside the consumer
price range) have 64 cores, maybe more. Sorry, but bitching in
hindsight is the easy way to look superior. I don't see Linux bitching
back *then* when AVX showed up. His forward-looking crystal ball was
just as cloudy as everyone else's. So, how many cores were in your home
computer back in 2013 when AVX came out? AVX isn't just about upping
the bit-width of FP calculations, but also about parallelization. How
many desktops nowadays have any apps on them that can use all 4 cores?

Not all CPUs are waiting to do something for end users. Some are
involved in highly complex computing, like animated computer graphics.
You think Zootopia was composed on a home computer? So, you think Intel
(or AMD) are going to tool up for a completely separate production line
for consumer vs high-graphics design platforms? There is an economy in
production by reusing existing manufacturing processes. Do consumer
platforms utilize AVX? Rarely. Why didn't Linus bitch when Intel added
Streaming SIMD Extensions (SSE)? How about all those non-gaming users
that don't care even about the old SSE extensions? Oh my God, the CPU
has something they don't need.

I suppose next Linus will bitch about increased parallelization in
Mozilla's Firefox. The next engine, Servo, takes advantage of the
memory safety and concurrency features of the Rust programming language.
Servo will use parallelism by using more cores for the rendering engine,
layout, HTML parsing, image processing, decoding, and other tasks that
can be isolated (into separate processes or threads to run on more
cores). Servo also makes further use of GPU-assisted acceleration, so
code running on a different processor. Would the GPU be needed if there
more core CPUs (real or multi-core) to parallelize the FP instructions?

I think GPU-assisted acceleration in web browsers started back in 2010,
but was just for web browsers. I remember some other apps used the GPU
for faster FP processing, but they seemed few and far between. More
video games are using AVX (AVX 2 more than AVX 512) since it is part of
the DirectX12 API. LOTS of users play video games on their home
computers, so AVX is really not that rare for use on low-end computing
platforms. AVX used to be shunned by game devs due to complexity in
coding.

Scalar, non-AVX :

void interpolate(vectorvectorint& mat)
{
for(int i=2; imat.size()-1; i=i+2)
for(int j=0; jmat[0].size(); j++)
{
mat[i][j] = mat[i-1][j] + 0.5f * (mat[i+1][j] - mat[i-1][j]);
}
}


Using AVX:

void interpolate_avx(vectorvectorint& mat)
{
for(int i=2; imat.size()-1; i=i+2)
for(int j=0; jmat[0].size(); j=j+8)
{
_mm256_storeu_si256((__m256i *)&mat[i][j],
_mm256_cvtps_epi32(_mm256_add_ps(_mm256_mul_ps(_mm 256_sub_ps(_mm256_cvtepi32_ps(_mm256_loadu_si256(( __m256i
*)&mat[i+1][j])), _mm256_cvtepi32_ps(_mm256_loadu_si256((__m256i
*)&mat[i-1][j]))), _mm256_set1_ps(0.5f)),
_mm256_cvtepi32_ps(_mm256_loadu_si256((__m256i *)&mat[i-1][j])))));
}
}

However, when mandated to programmers to code a game for maximum
performance, the AVX code runs 6.5 times faster! Simple coding with
slower performance, or complicated coding with faster performance. The
tradeoff is more cost in coding work, debugging, and optimizing hence
more time to achieve faster performance. Considering have video games
have upped the number of moving objects, physics modeling, and moving
texture change, some video games have insane requirements compared to
games dated over a decade ago.

Video games are real use of AVX. It's not just making benchmarks look
better. Guess Linus doesn't have bleeding edge hosts (in technology and
to his pocket) on which to run the most demanding video games. Is Linus
even a gamer? Oh wait, yeah, not that big a selection for Linux.

On 15/07/2020 19:42, VanguardLH wrote:
Is Linus even a gamer? Oh wait, yeah, not that big a selection for Linux.

He isn't anyway.

--
Brian Gregory (in England).

On 7/15/2020 2:42 PM, VanguardLH wrote:
Not all CPUs are waiting to do something for end users. Some are
involved in highly complex computing, like animated computer graphics.
You think Zootopia was composed on a home computer? So, you think Intel
(or AMD) are going to tool up for a completely separate production line
for consumer vs high-graphics design platforms? There is an economy in
production by reusing existing manufacturing processes. Do consumer
platforms utilize AVX? Rarely. Why didn't Linus bitch when Intel added
Streaming SIMD Extensions (SSE)? How about all those non-gaming users
that don't care even about the old SSE extensions? Oh my God, the CPU
has something they don't need.

Well, no, the SSE extensions were a big improvement over the old
stack-based FPU model. Directly accessible FP registers rather than
pushing and popping indirectly off of a stack. Even AMD's 3DNow achieved
this, requiring even less changes to the hardware (it just fixed the
existing FPU stack model), although AMD did not yet have sufficient
marketshare to push it widely onto the market. I think the point Linus
is making is that AVX takes FPU's to a state that no one asked for. When
the first version of AVX came out, and no one used it, well okay just a
mistake, then the second version came out, hoping that it would correct
the deficiencies of the first one, still kind of understandable. When
even that one wasn't used, and now we're at like version 3 or 4, none of
which are being used, then that's obviously gone too far.

Yousuf Khan

Yousuf Khan wrote:

On 7/15/2020 2:42 PM, VanguardLH wrote:
Not all CPUs are waiting to do something for end users. Some are
involved in highly complex computing, like animated computer graphics.
You think Zootopia was composed on a home computer? So, you think Intel
(or AMD) are going to tool up for a completely separate production line
for consumer vs high-graphics design platforms? There is an economy in
production by reusing existing manufacturing processes. Do consumer
platforms utilize AVX? Rarely. Why didn't Linus bitch when Intel added
Streaming SIMD Extensions (SSE)? How about all those non-gaming users
that don't care even about the old SSE extensions? Oh my God, the CPU
has something they don't need.

Well, no, the SSE extensions were a big improvement over the old
stack-based FPU model. Directly accessible FP registers rather than
pushing and popping indirectly off of a stack. Even AMD's 3DNow achieved
this, requiring even less changes to the hardware (it just fixed the
existing FPU stack model), although AMD did not yet have sufficient
marketshare to push it widely onto the market. I think the point Linus
is making is that AVX takes FPU's to a state that no one asked for. When
the first version of AVX came out, and no one used it, well okay just a
mistake, then the second version came out, hoping that it would correct
the deficiencies of the first one, still kind of understandable. When
even that one wasn't used, and now we're at like version 3 or 4, none of
which are being used, then that's obviously gone too far.

Yousuf Khan

Already pointed out: your "none of which are being used" is wrong. It
is being used. Video games use it, and those are not rare on Windows
platforms. Any game using DirectX 12 are utilizing AVX2. Scientific,
statistical, financial, encryption, and other programs can use it. Any
program using .NET Framework can use AVX. The latest versions of
Prime95 are optimized to use AVX. While it is used to stress test, that
was not its original or current intent which was to discover prime
numbers. Is prime hunting something that home users do? Of course not,
but it illustrates AVX *is* used.

https://www.tomshardware.com/reviews...de,5461-2.html
"By default, Prime95 automatically selects the newest instruction set
extension, such as AVX, AVX2, or even AVX-512."

Your claim AVX is not used is false.

To test, go into the BIOS settings and change the AVX offset, and then
monitor the core frequencies, like with MSI's Afterburner. Surprise, a
lot of video games use AVX. You'll see the core frequencies go down
relative to the AVX offset when running an AVX-enabled program. I don't
play many new games (I still wish the Thief series keep evolving since
stealth is so poorly done in newer games), but have read SofTR,
Darksiders 3, Monster Hunter Word, AC: Odyssey, and Overwatch use AVX.
Overclockers trying to maintain the highest but stable clock rates whine
when core frequencies drop due to AVX, and have to change the AVX offset
to up the freqs.

https://www.google.com/search?q=over...20avx%20offset

If the games weren't using AVX, overclockers wouldn't be stymied over
the reduction in core freqs (and possible instability from vcore
reduction).

https://www.youtube.com/watch?v=BXBSVT9lpGw

Notice the AVX mode has higher frame rates. Also, it seems the right
side (for AVX) seems sharper overall. Timemark 2:23 starts the charts.
Later the author shows AVX doesn't improve performance in all games that
implement AVX. Sometimes AVX helps, sometimes not (but it's not worse).
I'm not into game programming, so I'll let someone else expert in that
note why AVX doesn't do better than SSE.

On 2020-07-15 11:42, VanguardLH wrote:
Is Linus
even a gamer? Oh wait, yeah, not that big a selection for Linux.

Linux is not tied with Windows for gaming. Take
a gander at:

Fedora 31 | Features, Gaming, and New Daily Driver
https://www.youtube.com/watch?v=1P8oBlOTBho

On 2020-07-16 11:35, T wrote:
isÂ*not

"is now"

Stinking typos

T wrote:

VanguardLH wrote:

Is Linus even a gamer? Oh wait, yeah, not that big a selection for
Linux.

Linux is not tied with Windows for gaming. Take
a gander at:

Fedora 31 | Features, Gaming, and New Daily Driver
https://www.youtube.com/watch?v=1P8oBlOTBho

You didn't provide a timemark for the related content, and I wasn't
going to watch all of the 22 minute video, so I moved the slider to skim
through it. The author started talking about Steam on Linux which could
now detect the native OS platform to know which game titles to present.
Steam represents about 78% of the marketshare for computer games. I saw
something about them using a compatibility shim to run Windows games on
Linux platforms eliminating the need to run Steam and the Windows games
inside of WINE. Wonder how the benchmarks reflect the performance of a
Windows game running inside of WINE versus running the Windows game atop
Steam's shim.

https://itsfoss.com/steam-play/

Oh, so Steam Play simply provides a fork of WINE as its shim between the
native OS platform and the Windows-only game. The Windows games will
likely be impacted the same whether ran inside of WINE or Steam's
variant of WINE. I didn't even bother to address running anything
Windows inside of WINE or via any other emulation layer, like VMWare
Player for Linux running Windows as a guest OS and then running a
Windows game inside of that virtual machine. That something is doable
doesn't mean it should be.

That still means the games were *not* developed for the Linux platform.
They were written for the Windows platform. Guess I should've qualified
my statement by saying:

"Oh wait, yeah, not that big a selection of native Linux games. "

Do hardcore gamers even bother with WINE? Conversely, everything Linux
can be played on Windows, too, so the user could use a Windows platform
to play native Windows games and emulated Linux games. Is there much
draw for that scenario? You can even play Android apps on Windows by
using a shim aka emulator, like Bluestacks. There's native-on-native,
and then there are less-than-ideal workarounds.

VanguardLH wrote:
You didn't provide a timemark for the related content, and I wasn't
going to watch all of the 22 minute video, so I moved the slider to skim
through it. The author started talking about Steam on Linux which could
now detect the native OS platform to know which game titles to present.
Steam represents about 78% of the marketshare for computer games. I saw
something about them using a compatibility shim to run Windows games on
Linux platforms eliminating the need to run Steam and the Windows games
inside of WINE. Wonder how the benchmarks reflect the performance of a
Windows game running inside of WINE versus running the Windows game atop
Steam's shim.

No all Steam games on Linux are Windows games running in WINE, many are
truly ported. I've got the Borderland games and they are ports not
running in WINE. Proton and WINE just extend selection for old games
avoiding the need to port.

--
Take care,

Jonathan
-------------------
LITTLE WORKS STUDIO
http://www.LittleWorksStudio.com

"Jonathan N. Little" wrote:

VanguardLH wrote:

The author started talking about Steam on Linux which could now
detect the native OS platform to know which game titles to present.
Steam represents about 78% of the marketshare for computer games. I
saw something about them using a compatibility shim to run Windows
games on Linux platforms eliminating the need to run Steam and the
Windows games inside of WINE.

No all Steam games on Linux are Windows games running in WINE, many
are truly ported. I've got the Borderland games and they are ports
not running in WINE. Proton and WINE just extend selection for old
games avoiding the need to port.

And does that somehow lopside the bias of game count to make native
Linux games far exceed those native games available on Windows? Of
course not. A game that had been ported to be a native Linux app is
obviously no longer a Windows app. A ported Windows game becomes a
native Linux game. The count of Linux games, whether native or ported
to make native, are still meager compared to the count of native games
on Windows.

Steam Play (Steam for Linux) detects the platform for the game probably
via a manifest for the game specifying its native platform. If it's a
native Linux game, it just loads it in Linux. If a Windows game, it
uses its WINE variant (aka Proton) to run the Windows game in that
emulator running atop Linux.

https://www.extremetech.com/gaming/2...ows-only-games

The confirmed list of Windows-only games that are compatible atop
Steam's Proton variant of is small. That's just the ones that Steam has
confirmed are compatible.

https://emulation.gametechwiki.com/index.php/Proton

has a hyperlink pointing to a list of app manifests/mappings for 100+
compatible Windows games. There's also a link to user-reported game
compatibility.

Proton converts the DX 10/11 calls to Vulkan to help keep game
performance similar to the Windows game when ran native on Windows.
That is dependent on the available of proprietary Linux drivers for
video hardware, the efficiency in coding the Linux video driver, and
compatibility of the Linux driver provided by the video maker to run on
other Linux variants (most don't list just Linux but some variant as
supported).

Regardless of the workarounds, they still don't alter which are native
Linux games and which are native Windows games, and the huge disparity
in counts between them. As noted, you can run Linux stuff on Windows,
but that doesn't magically mutate them into native Windows apps. Linux
marketshare floats around 2%, so obviously the game authors are going to
target the market that has the biggest ROI. That's not Linux.

I'm not a Windows proselytizer or Linux defender. I believe in using
the platform that best suits the task. Sorry, I still don't see Linux
as the best choice for a gaming platform.

On 2020-07-16 14:01, VanguardLH wrote:
T wrote:

VanguardLH wrote:

Is Linus even a gamer? Oh wait, yeah, not that big a selection for
Linux.

Linux is not tied with Windows for gaming. Take
a gander at:

Fedora 31 | Features, Gaming, and New Daily Driver
https://www.youtube.com/watch?v=1P8oBlOTBho

You didn't provide a timemark for the related content, and I wasn't
going to watch all of the 22 minute video, so I moved the slider to skim
through it. The author started talking about Steam on Linux which could
now detect the native OS platform to know which game titles to present.
Steam represents about 78% of the marketshare for computer games. I saw
something about them using a compatibility shim to run Windows games on
Linux platforms eliminating the need to run Steam and the Windows games
inside of WINE. Wonder how the benchmarks reflect the performance of a
Windows game running inside of WINE versus running the Windows game atop
Steam's shim.

https://itsfoss.com/steam-play/

Oh, so Steam Play simply provides a fork of WINE as its shim between the
native OS platform and the Windows-only game. The Windows games will
likely be impacted the same whether ran inside of WINE or Steam's
variant of WINE. I didn't even bother to address running anything
Windows inside of WINE or via any other emulation layer, like VMWare
Player for Linux running Windows as a guest OS and then running a
Windows game inside of that virtual machine. That something is doable
doesn't mean it should be.

That still means the games were *not* developed for the Linux platform.
They were written for the Windows platform. Guess I should've qualified
my statement by saying:

"Oh wait, yeah, not that big a selection of native Linux games."

Do hardcore gamers even bother with WINE? Conversely, everything Linux
can be played on Windows, too, so the user could use a Windows platform
to play native Windows games and emulated Linux games. Is there much
draw for that scenario? You can even play Android apps on Windows by
using a shim aka emulator, like Bluestacks. There's native-on-native,
and then there are less-than-ideal workarounds.


Titus starts in with Lutris at about 7:25

T wrote:

On 2020-07-16 14:01, VanguardLH wrote:
T wrote:

VanguardLH wrote:

Is Linus even a gamer? Oh wait, yeah, not that big a selection for
Linux.

Linux is not tied with Windows for gaming. Take
a gander at:

Fedora 31 | Features, Gaming, and New Daily Driver
https://www.youtube.com/watch?v=1P8oBlOTBho

You didn't provide a timemark for the related content, and I wasn't
going to watch all of the 22 minute video, so I moved the slider to skim
through it. The author started talking about Steam on Linux which could
now detect the native OS platform to know which game titles to present.
Steam represents about 78% of the marketshare for computer games. I saw
something about them using a compatibility shim to run Windows games on
Linux platforms eliminating the need to run Steam and the Windows games
inside of WINE. Wonder how the benchmarks reflect the performance of a
Windows game running inside of WINE versus running the Windows game atop
Steam's shim.

https://itsfoss.com/steam-play/

Oh, so Steam Play simply provides a fork of WINE as its shim between the
native OS platform and the Windows-only game. The Windows games will
likely be impacted the same whether ran inside of WINE or Steam's
variant of WINE. I didn't even bother to address running anything
Windows inside of WINE or via any other emulation layer, like VMWare
Player for Linux running Windows as a guest OS and then running a
Windows game inside of that virtual machine. That something is doable
doesn't mean it should be.

That still means the games were *not* developed for the Linux platform.
They were written for the Windows platform. Guess I should've qualified
my statement by saying:

"Oh wait, yeah, not that big a selection of native Linux games."

Do hardcore gamers even bother with WINE? Conversely, everything Linux
can be played on Windows, too, so the user could use a Windows platform
to play native Windows games and emulated Linux games. Is there much
draw for that scenario? You can even play Android apps on Windows by
using a shim aka emulator, like Bluestacks. There's native-on-native,
and then there are less-than-ideal workarounds.


Titus starts in with Lutris at about 7:25

He first shows installing Lutris (Open Gaming Platform) before
installing Steam Play. Is Lutris even needed to use Steam's dispatcher
to decide if a game's manifest says it is Windows-only to then run it
under Steam's Proton variant of WINE? Isn't Lutris a Linux game library
manager and launcher, and perhaps across multiple sources (Steam,
battle.net, GOG)?

The video author says Lutris has no documentation. Really? Learning is
solely by trial-and-error, or pleading for info in a user community?

Before all that, he installed rpmFusion to get all the libs that Redhat
doesn't include on which Lutris and Steam Play might be dependent.
Install this, a must. Maybe install that. Then install Steam Play. I
take it Lutris and Steam Play won't grab, download, and install any libs
they are dependent upon. Seems this could be further streamlined for a
bigger lure to users to leave Windows. Maybe the chained installs are
needed just for Fedora.

On 2020-07-16 1:35 p.m., T wrote:
On 2020-07-15 11:42, VanguardLH wrote:
Is Linus
even a gamer?Â* Oh wait, yeah, not that big a selection for Linux.

Linux is not tied with Windows for gaming.Â* Take
a gander at:

Fedora 31 | Features, Gaming, and New Daily Driver
https://www.youtube.com/watch?v=1P8oBlOTBho

You make joke, Yes? :-)

Rene

Rene Lamontagne wrote:
On 2020-07-16 1:35 p.m., T wrote:
On 2020-07-15 11:42, VanguardLH wrote:
Is Linus
even a gamer? Oh wait, yeah, not that big a selection for Linux.

Linux is not tied with Windows for gaming. Take
a gander at:

Fedora 31 | Features, Gaming, and New Daily Driver
https://www.youtube.com/watch?v=1P8oBlOTBho

You make joke, Yes? :-)

Rene


Are we playing "Sodoku" yet ?

Paul

On 2020-07-16 6:08 p.m., Paul wrote:
Rene Lamontagne wrote:
On 2020-07-16 1:35 p.m., T wrote:
On 2020-07-15 11:42, VanguardLH wrote:
Is Linus
even a gamer?Â* Oh wait, yeah, not that big a selection for Linux.

Linux is not tied with Windows for gaming.Â* Take
a gander at:

Fedora 31 | Features, Gaming, and New Daily Driver
https://www.youtube.com/watch?v=1P8oBlOTBho

You make joke, Yes?Â* :-)

Rene


Are we playing "Sodoku" yet ?

Â*Â* Paul

I don't know how to play 'Sodoku'
Too old to start now. :-)

Rene